Every brief rain brings hope that California is not slipping back into drought. And local water officials assure us that we have enough water to get us through the year, even if the drought resumes. They point to state and local reservoirs filled to their historic averages or more, a deal to access water from the Imperial Valley and added supply from a new desalination plant in Carlsbad.

But what if the drought never ended? What if last year’s rain was an anomaly, and climate change made the nine dry years that preceded it the new normal? Climatologist Bill Patzert of Caltech recently observed, “When you call an end to the drought after one wet year, that’s false hope.” Yet our water policies continue to treat that “false hope” as reality.

Suppose we assumed years ago, when the drought was well underway, that this condition would prevail indefinitely. What might our water policies have become? Presumably, they would have resembled those of places that concluded long ago they would never have reliably plentiful water.

Speaking at UCSD two years ago, water agency officials from Israel described the evolution of their water policies since the 1970s, when they recognized their water use practices were unsustainable. First, they emphasized conservation in both homes and businesses. Next, capturing and storing even the limited rainfall. Then, treating and reusing wastewater. And, after all that, turning to desalination to fill remaining needs. Today, the country not only has a stable water supply but has become a center for advanced water technology.

We should learn from that experience. The San Diego region too has placed major bets on expanding its water storage capacity, committing to water recycling programs and generating desalinated seawater. But we have fallen short on the first step — emphasizing conservation.

San Diego has always been highly vulnerable to water shortages, due to minimal average rainfall, limited groundwater basins and a location far from major water sources. Through aggressive development of closer water resources, we have substantially reduced our reliance on water imported from outside the region. Still, more than three-fourths of our needs continue to be met with water from Northern California or the Colorado River. Currently, the snowpack in the Sierras is at about one-seventh of historical average, meaning far less snowmelt for the State Water Project. Meanwhile, the Colorado River is expected to receive barely half the average runoff from the Rockies.

Conservation alone will not solve our water supply needs, but it is where we should start, and where we should place continuing emphasis. The least expensive and most reliable gallon of water is the one we don’t consume in the first place. While we have increased efficiency over recent decades, we still consume more than twice as much water per capita as people in other modern, industrialized countries. And, with over 60 percent of all water going to agriculture, and about two-thirds of residential water going to landscaping, the rainfall shortage this season has boosted consumption even as supplies dwindle.

The cost of water is also a concern, as water charges by the Metropolitan Water District are up over two-thirds in the last decade, and desalinated water costs about twice as much as imported water. But water is undervalued, with tap water still costing less than a penny a gallon, and most of that represents the fixed cost of infrastructure rather than water itself. The fundamental issue is long-term sustainability. Cost can be addressed through lifeline rates for low-income households, as is done with other utilities.

Gov. Jerry Brown imposed a statewide urban water use reduction of 25 percent in response to drought conditions in 2015, resulting in a saving of nearly 900 billion gallons before the restrictions were lifted last year. Seeing supply dropping and consumption rising, the State Water Resources Control Board is considering adopting permanent conservation requirements.

Even that will not be enough. Governments lack the resources to enforce those limits and few people are comfortable turning in their neighbors. Water agencies offer conservation incentives, but they are underpublicized.

We need to foster a water conservation ethic, emphasizing the value of water and the importance of treating it like the vital resource it is. After all, human life can only exist about seven days without it.

Driving home that message will require us to emulate the experience of Israel, Australia and other dry places. There, public officials, civic leaders, mass media and educational institutions have joined in ongoing, well-orchestrated campaigns to raise public consciousness and instill understanding of the need for conservation. And to maintain that understanding indefinitely. Under current circumstances, we cannot afford to do less.

Lowe is a land-use lawyer who chaired the San Diego City Council Water Policy Implementation Task Force.